This invention relates to fuel systems for a gas turbine engine and more particularly to a fuel divider valve that can also be employed for sequential start-up of the engine.
As is well known, to obtain ignition in a jet engine the fuel/air ratio must be maintained above some minimum value in the vicinity of the nozzles where lighting is to occur. Normally ignition is started in one or two places and the flame rapidly propogates all around the burner. In some engines this rapid addition of energy will drive the compressor into stall unless massive compressor bleed provisions are made. This stall condition may be alleviated by sequentially lighting, at a controlled rate, selected areas at the correct local fuel/air ratio in the burner so that engine acceleration to idle can be accomplished at a rate that will not drive the compressor into stall. To this end this invention teaches a fuel divider valve for a single stage burner which will provide metering to individual fuel nozzles and sequential lighting capability without changing the fuel scheduling characteristics of the fuel control. Because of the uniqueness of this valve it lends itself to being used as a flow divider distributor and metering valve because of its ability to accurately proportion the flow through the discharge ports over a wide fuel flow band.